I would think someone would offer one-way rentals between PIT and JST -- probably Hertz.. As per US not serving PDX that's a sore spot to many of US fliers, including me. One city I'd like to visit but haven't yet, primarily due to no US service. One of the few and between highlights of the merger would be non-stop service PIT-PDX on the new UA.

As doc mentioned both JST and Fallingwater are East of Pittsburgh, but JST is northeast while Fallingwater is southeast. I'll be in PIT July 7 so if you have a long layover/wait at the airport, let me know.